Torque Convertor or Bell Housing Plug

I have a 2001 V6 Mustang and I have a question about what area underneath the car I am looking at.

I am not a car guru. I had a 1966 Mustang growing up and when I worked on it, everything was simpler. More expensive, but easier to work on. Now with my 2001 I have virtually no clue as to what I am looking at.

My question is, I have some fluid coming out from under the car and I am trying to figure out where it is coming from.

In the picture below, what exactly am I looking at where the drop of what I believe is transmission fluid? What is that plug and what kind of fluid would the box above it contain?

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Torque Converter bellhousing. That plug is just a simple dust/fluid leak plug. It's real purpose.. well I don't know. The guys at Ford dont even know. They think it was put in as some kind of catch area for rear fluid leaks. The fluid looks more like motor oil than tranny fluid. Either coming from a leak in the drain pan plug, a recent oil change gone messy... or a minor oil pan gasket and/or rear main seal leak. Touch the fluid with your finger and smell it.. seriously. If it smells like exhaust, oil, and gas then it's engine oil. If it has a tad of sweet n tart smell..it's tranny fluid. Just dont lick it ..... :p